Rotary fluid motors



Apr 17, 1962 c. H. RYSTROM 3,029,794

. ROTARY FLUID MOTORS Filed March 2, 1960 2 Sheets-Sheet 1 14 61 INVENTOR. fiaf/es'figjwirom April 17, 1962 c. H. RYSTROM 3,029,794

ROTARY FLUID MOTORS Filed March 2, 1960 2 Sheets-Sheet 2 ENTOR.

Unite States Patent 3,029,794 ROTARY FLUID MOTORS Charles H. Rystrom, Barrington, 111., assignor to Ammco Tools, Inc, North Chicago, Ill., a corporation of Illinois Filed Mar. 2, 1960, Ser. No. 12,461 8 Claims. (Cl. 121--87) This invention relates to rotary fluid motors and has to do more particularly with a fluid motor of the type having a rotor with radially movable displacer elements and novel means for maintaining the displacer elements in contact with the inner peripheral wall of the displacement chamber.

In rotary fluid motors of the type wherein the rotor carries a series of displacer elements radially slidable in sockets in the rotor body for engagement with the inner peripheral wall of the displacement chamber, a force in addition to centrifugal force is required in order to maintain the displacer elements in contact with the peripheral wall. Heretofore, fluid pressure has been applied under the displacer elements to urge them outwardly. It is necessary to supply such fluid at higher pressure than the pressure of the fluid on the outer ends of the displacer elements in order to insure that the displacer elements are maintained against the peripheral wall and consequently the fluid under normal inlet pressure cannot be employed for this purpose.

In order to provide the required pressure differential between the fluid on the inner and outer ends of the displacer elements, motors have been developed wherein a portion of the incoming fluid is supplied under line pressure to the inner ends of the displacer elements. The remainder of the fluid is conducted through a pressure-reducing valve externally of the motor and thence to the displacement chamber through an isolating chamber in the motor whereby the fluid under reduced pressure is isolated from the fluid under full line pressure. The use of such an external valve requires the use of a thread pipe connected to the motor casing.

An object of the present invention is to provide a motor of the type having a rotor carrying radially movable displacer elements which are urged outwardly against the peripheral wall of the displacement chamber by fluid pressure and wherein a pressure-reducing valve is provided in the motor casing and so connected that the fluid under full line pressure is supplied to the inner ends of the displacer elements to urge them outwardly and fluid under reduced pressure is supplied to the outer portions of the displacer elements to drive the motor.

Another object of the present invention is to provide a motor of the type having a rotor carrying radially movable displacer elements which are urged outwardly against the peripheral wall of the displacement chamber by fluid pressure and wherein fluid is supplied to the inner ends of the displacer elements at a greater pressure than to the outer portions, the arrangement being such that no separate chamber is required for isolating the fluid under the diflerent pressures.

Still another object is to provide a rotary fluid motor having a pressure-reducing valve connected between the inlet and the displacement chamber which is of such construction and arrangement that it is entirely within the motor housing and requires a minimum of space.

A further object is to provide a rotary fluid motor having a pressure-reducing valve therein which is so constructed and arranged that it can be conveniently and economically constructed and assembled in the motor housing.

Other objects and advantages will appear from the following description taken in connection with the appended drawings, wherein:

FIGURE 1 is a vertical, longitudinal section through a motor embodying the present invention;

FIGURE 2 is sectional view taken along line 2-2 of FIGURE 1;

FIGURE 3 is an exploded, elevational view of a portion of the structure of FIGURE 1;

PEGURE 4 is a View taken along line 44 of FIG- URE 3;

FIGURE 5 is a sectional view taken along line 5-5 of FIGURE 4;

FIGURE 6 is a view taken along line 66 of FIG- URE 3;

FIGURE 7 is a sectional view taken along line 7--7 of FIGURE 1; and

FIGURE 8 is a view taken along line 88 of FIG- URE l.

The motor comprises a casing to of generally annular form and having an interior wall surface 11 defining a displacement or motor chamber 12. extending axially through the casing 16. The inner wall surface 11 is of non-circular form and is provided with two lobes or enlargements diametrically spaced about the periphery of the wall surface and providing portions of maximum radius merging into alternate portions of minimum radius. A rotor 14, hereinafter described more fully, is disposed in the displacement chamber 12 and has maximum clearance with the maximum radius portions to provide between the rotor and the maximum radius portions displacement cavities or zones 15 and to provide with the remaining portions of the inner wall of the casing minimum clearance with the rotor.

A portion of each cavity adjacent to leading or entrance portion may be designated as an inlet zone and the portion adjacent to trailing or exit portion may be designated an outlet zone with the portion of each displacement cavity between the inlet and outlet zones being known as the displacement zone.

The ends of the casing 19 are closed by end heads 29 and 21 which are secured together and against the ends of the casing in a suitable manner as by bolts 22 extending through bores 23 in the end heads. The end head 21 is of generally cupped shape with the open end abutting the motor casing 10 as seen particularly in FIG. 1 of the drawings. At its open end, the end head 21 is formed with a counterbore 30 adapted to receive the casing Jill therein and to provide a shoulder 31 against which the casing lit seats. A peripheral notch 32 is formed in the end wall of the casing "10 which provides with the shoulder and adjacent wall an annular chamber which receives a sealing ring, which preferably is a O ring 33, for sealing the joint between the casing 10 and the end head 21. The casing 19 is suitably sealed against the end head 20, as by a sealing ring, which preferably is an 0 ring 34, seated in an annular groove 35 formed in the inner face of the end head 20.

The end head 21 is formed with a central hub 40 extending inwardly from its inner wall in the direction of its open end. A drive shaft 41 is rotatably journaled in the hub 40 and extends through the rotor 14 and is journaled in a bearing 42 disposed in a bearing socket 43 formed in the end head 20. The drive shaft 41 is held in the journal by a collar 4 secured to the shaft 3 by a pin 45. The drive shaft 21 supports the rotor 14 and is drivingly connected thereto by a splined connection 46. The shaft 41 is sealed in the end head 21 by a seal 47 of suitable construction.

The rotor 14 is circular in outline and includes a body 50 provided with a plurality of circumferentially spaced, radially disposed sockets or grooves which extend through the length of the rotor body and are adapted to receive displacer elements which are radially movable in the sockets. Each socket includes an enlarged outer portion 55 a narrow slot-like intermediate portion 56 and an inner end portion 57 which preferably is of greater wall-to-wall dimension than the intermediate portion. Each displacer element includes a roller 58 disposed and radially slidable in the outer portion of the socket and a blade or vane 59 radially slidable in the outer, intermediate and inner portions of the socket and adapted to bear against the corresponding roller. The widened inner end portions 57 of the sockets are adapted to receive fluid under pressure to urge the corresponding vanes 59 outwardly against the rollers 56 and thus maintain the latter in engagement with the inner wall surface of the casing 10. in a known manner.

The end head 21 defines a cavity 60 in which a pressure plate or thrust plate 61 is mounted for sliding movement in an axial direction toward and into engagement with the casing 10, the rollers 58, the blades 59, and the rotor body 50.

The pressure plate 61 is formed with a stepped bore having a portion 62 adapted to receive the hub 40 and which is spaced therefrom, a reduced bore portion 63 forming with a notched portion 64 on the hub an annular recess for a sealing ring such as an O ring 65. The pressure plate 61 has a further reduced bore portion 66 which receives the collar 44 and a smaller bore portion 67 which receives the shaft 41.

Disposed in the cavity 60 is a backing plate 70 which is slidably disposed in the bore of the cavity and normally seated against the inner end wall 71 thereof. The backing plate is formed with a tapered bore 69 whereby it is spaced from the hub 40 and thus a pressure chamher is provided between the hub on the one hand and the pressure plate and the backing plate on the other hand.

The thrust plate 61 is provided with an inner face 72 which is inclined to the axis of the end head 21, and the backing plate 70 is provided with a complementary, inclined face 73 which abuts the face 72. The thrust plate is held against turning movement by a pin 74 slidable in the slot 75 in the thrust plate, the slot being of sufi'icient length to permit the thrust plate to be urged against housing 10, the rollers 58, and the blades 56, when fluid pressure is present in the pressure chamber 6%.

The end head 21 is provided with an inlet opening 80 communicating with a passage 81 in the backing plate 70 (FIG. 7). Communicating with the passage 81 is a valve port 82 controlled by a check valve 83 which takes the form of a ball normally urged against the seat by a spring 84. The port 82 communicates with the passage 84 in which the spring 85 is located which spring 85 normally urges the ball 83 against its seat. The spring is compressed against a plug 86 secured in the passage 8-.- by a ring 87 and sealed by an 0 ring seal 33.

The passage 84 communicates with the passage 89 which opens into the pressure chamber 63 whereby fluid may flow from the inlet passage 80 to the passage 81, valve port 82, the passage 84, and the passage 89 into the chamber 60.

Leading from the chamber 60 are inlet passages 90 which open into the displacement chamber 12 through inlet ports 91 and supplemental ports 92.

Means are provided for introducing fluid under inlet pressure inwardly of the blades 59, which means includes a passage 93 leading from the passage 81 to a passage 94 in the thrust plate 61 and terminating at an annular groove 95 formed in the thrust plate 61 and com- L municating with the displacement chamber inwardly of the blades 59. The joint between the passage 93 and the passage 94 is sealed by an O ring 97 seated in a notch 97 formed in the backing plate 79.

Outlet ports 190 are provided in the thrust plate 61 and lead from the displacement chamber 12 and open into an outlet passage 161, of generally annular form provided in the thrust plate 61. The outlet passage ltll opens into an outlet opening 102 formed in the end head 21 whereby fluid may flow from the displacement chamber 12 through the discharge or outlet ports 100 and the passage 101 and be discharged from the housing.

In the use of the motor of the present invention, the inlet opening (it) is suitably connected to a source of fluid (not shown) under pressure. Fluid flows through the inlet 80, the passage 81, the valve port 32 and opens the valve 83, and then flows through the passage 84 and the passage 89, and then into the chamber 60. From the chamber 60, the fluid flows through the passages and the inlet ports 91 into the displacement chamber 12. The pressure of the fluid acting against the rollers 58 causes the rotor 14 to rotate (in a counterclockwise direction as viewed in FIG. 2). As the rotor is rotated, the fluid flows from the displacement chamber 12 out through the outlet ports and then through the passage 101 and the outlet opening 102. The latter preferably is connected to a discharge pipe for conducting the discharge fluid away from the motor.

Fluid also flows from the passage 81 through the passages 93 and 94 and the annular grooves 95 and 96, and the pressure thereof is applied inwardly of the blades 56 to urge them and the abutting rollers outwardly whereby the rollcrs remain in engagement with the inner wall of the displacement chamber so long as any fluid under pressure is introduced into the housing.

The fluid under pressure in passing through the check valve 83 suffers a pressure drop or loss so that the fluid in the displacement cavities 15 is at a lower pressure than the fluid in the socket portions 57 inwardly of the blades 59. Accordingly, the blades 59 are always urged outwardly to maintain the rollers against the inner wall so long as there is any fluid under pressure within the housing.

The pressure differential offered by the check valve 83 may be any suitable amount but is selected to be sufficient to insure that the blades are always urged 0utwardly. For example, with an inlet pressure of 1,065 lbs., the valve 83 may provide a pressure drop of 65 lbs., so that the pressure applied to the rollers to rotate the rotor is approximately 1,000 lbs. It will be understood, of course, that the pressure drop provided by the check valve may be any suitable amount and which is Suthcient to insure that the blades are maintained in their outer positions during the rotation of the rotor.

In order to permit full radial movement of the rollers 58 in their sockets and to increase the displacement capacity of the motor, means are provided for permitting the free flow of fluid between the displacement cavities respectively and the portions of the sockets inwardly of the rollers. To this end I provide radial grooves in one or both, and preferably both, radial edges of the outer portions of each socket. As the rollers are moved in and out in their respective sockets by their engagement with the inner wall upon rotation of the rotor fluid flows past the rollers and into and out of the outer socket portions inwardly of the rollers.

It will be seen from the foregoing that the present invention provides a motor wherein a pressure reducing valve is provided within the motor casing so connected that the fluid under full line pressure is supplied to the inner ends of the displacer elements to urge them outwardly and fluid under reduced pressure is supplied to the outer portions of the displacer elements to drive the motor. The present invention provides a construction wherein no separate chamber is required for isolating the fluid under the different pressures. Moreover, there is no need for a third pipe connected to the motor casing as there is where a separate external auxiliary valve is used.

Certain features disclosed but not claimed herein are disclosed and claimed in my copending applications Ser. No. 807,359, filed April 20, 1959; Ser. No. 832,521, filed Agugust 10, 1959; and Ser. No. 10,496, filed February 23, l 60.

What is claimed is:

l. A rotary fluid motor comprising a housing including a pair of end heads one of which has inlet and outlet ports therein, a generally annular rotor casing between said end heads and having an inner wall defining a displacement chamber, a rotor in said casing including a rotor body having a peripherally arranged series of slots and displacer elements slidable inwardly and outwardly in said slots for engagement with said inner wall, rigid wall means slidable axially in said housing into engagement with said rotor casing and defining an inlet chamber and an outlet chamber, said means having an outlet passage connecting said outlet port and said outlet chamber, an inlet passage connecting said inlet port and said inlet chamber, a passage connecting said inlet chamber and said displacement chamber, and a passage connecting said inlet port and said slots inwardly of said displacer elements and means in said housing for reducing the pres- ;ure of the fluid delivered to said displacement cham- 2. A rotary fluid motor comprising a housing including a pair of end heads one of which has inlet and outlet ports therein, a generally annular rotor casing between said end heads and having an inner wall defining a displacement chamber, a rotor in said casing including a rotor body having a peripherally arranged series of slots and displacer elements slidable inwardly and outwardly in said slots for engagement with said inner wall, rigid Wall means slidable axially in said housing on the same side of said casing as said one end head into engagement with said rotor casing and dividing the interior of said housing into an inlet chamber and an outlet chamber, said outlet port being connected to said outlet chamber, said means having an inlet passage connecting said inlet port and said inlet chamber, a passage connecting said inlet chamber and said displacement chamber, a branch passage connecting said inlet passage and said slots inwardly of said displacer elements and pressure reducing means in said inlet passage inwardly beyond said branch passage.

3. A rotary fluid motor comprising a housing including a pair of end heads one of which is concave and has inlet and outlet ports therein, a generally annular rotor casing between said end heads and having an inner wall defining a displacement chamber, a rotor in said casing including a rotor body having a peripherally arranged series of slots and displacer elements slidable inwardly and outwardly in said slots for engagement with said inner wall, rigid wall means slidable axially in said one end head into engagement with said rotor casing and dividing the interior of said housing into an inlet chamber and an outlet chamber, said means having an outlet passage connecting said outlet port and said outlet chamber, an inlet passage connecting said inlet port and said inlet chamber, a passage connecting said inlet chamber and said displacement chamber, a branch passage connecting said inlet passage and said slots inwardly of said displacer elements and pressure reducing means in said inlet passage inwardly beyond said branch passage.

4. A rotary fluid motor comprising a housing including a pair of end heads one of which has inlet and outlet ports therein, a generally annular rotor casing between said end heads and having an inner wall defining a displacement chamber, a rotor in said casing including a rotor body having a peripherally arranged series of slots and displacer elements slidable inwardly and outwardly in said slots for engagement with said inner wall, rigid thrust means slidable axially in said housing into engagement with said rotor casing and defining an inlet chamber and an outlet chamber, said means having an outlet passage connecting said outlet port and said outlet chamber, an inlet passage connecting said inlet port and said inlet chamber, a passage connecting said inlet chamber and said displacement chamber, a branch passage connecting said inlet passage and said slots inwardly of said displacer elements and pressure reducing means in said inlet passage inwardly beyond said branch passage.

5. A rotary fluid motor comprising a housing including a pair of end heads one of which is concave and having a side wall and end Wall and inlet and outlet ports therein, a generally annular rotor casing secured between said end heads and having an inner wall defining a displacement chamber, -a rotor in said casing including a rotor body having a series of peripherally arranged slots and a plurality of displacer elements slidable inwardly and outwardly of said rotor body in said slots and into engagement with said inner Wall, a rigid thrust plate slidable axially in said concave end head and closing one end of said rotor casing, a backing plate slidable axially in said concave end head between said thrust plate and the end wall of said end head and abutting said thrust plate, said thrust plate and said backing plate having a first passage extending serially therethrough from said inlet port to said slots inwardly of said displacer elements and a second passage extending serially therethrough from said first passage to said displacement chamber, said thrust plate having a passage therethrough leading from said displacement chamber to said outlet port, and pressure reducing means in the portion of said second passage which is located in said backing plate.

6. A rotary fluid motor comprising a housing including a pair of end heads one of which has inlet and outlet ports therein, a generally annular rotor casing between said end heads and having an inner wall defining a displacement chamber, a rotor in said casing including a rotor body having a peripherally arranged series of slots, and displacer elements slidable inwardly and outwardly in said slots for engagement with said inner wall, a rigid thrust plate slidable axially in said housing against one end of said rotor casing and defining with said housing an inlet chamber and having a peripheral groove defining with said housing an outlet chamber connected with said outlet port and having passages connecting said displacement chamber and said outlet chamber, a backing plate slidable axially in said housing on the opposite side of said thrust plate from said rotor casing and having a passage therein connecting said inlet port and said inlet chamber, said thrust plate having passages connecting said inlet chamber and said displacement chamber, a check valve in said passage in said backing plate, and a passage in said thrust plate connecting the passage in said backing plate ahead of said valve and said slots inwardly of said displacer elements.

7. A motor as claimed in claim 6 wherein said thrust plate is formed with a face inclined to the axis of said rotor and said backing plate has a face inclined similarly to the inclined face on said thrust plate and abutting said first face.

8. A rotary fluid motor comprising a housing including a pair of end heads one of which has inlet and outlet ports therein, a generally annular rotor casing between said end heads and having an inner wall defining a displacement chamber, a rotor in said casing including a rotor body and a plurality of displacer elements slidable inwardly and outwardly peripherally of said rotor body for engagement with said inner wall, a rigid thrust plate slidable axially in said housing against one end of said rotor casing and defining with said housing an inlet chamber and having a peripheral groove defining with said housing an outlet chamber communicting with said outlet port and having passages connecting said displacement 7 chamber and said outlet chamber, said thrust plate defining with said one end head an inlet chamber on the opposite side of said thrust plate from said rotor casing, said thrust plate having passages connecting said inlet chamber and said displacement chamber, a backing plate 5 slidable axially in said housing on the opposite side of said thrust plate from said rotor casing and having a passage eonnecting said inlet port and said inlet chamber and a check valve in said last-named passage.

References Cited in the file of this patent UNITED STATES PATENTS 2,521,997 Rosaen Sept. 12, 1950 2,636,481 Rosaen Apr. 28, 1953 2,738,774 Rosaen Mar. 20, 1956 FOREIGN PATENTS 654,808 Great Britain h June 27, 1951 

